Yes, definitely. When you are entering an employment contract with a prospective candidate, you mention certain terms & conditions of service. One such term & condition is that of a probation period. Thus in the event of completion of probation period, employer need to notify the employee about his confirmation, through a letter.
Benefits, the employee enjoying in the company, during probation period and during confirmation period, after probation is also different.So also with Separation clause and Notice period.